Chaperone mediated autophagy modulates microglia polarization and inflammation via LAMP2A in ischemia induced spinal cord injury

Abstract

Spinal cord injury (SCI)-induced ischemic delayed paralysis is one of the most serious side effects of aneurysms surgeries. Recent studies prove that the activation of autophagy, including macroautophagy and micro-autophagy pathways, occur during SCI-induced brain neuron damage. However, the role of chaperone mediated autophagy (CMA) during SCI remains to be unveiled. In the present work, rat model of delayed paralysis after aneurysms operation and adenovrius induced LAMP2A knockdown in microglia cells were applied in the present work to investigate the involvement of LAMP2A-mediated CMA in the aneurysm operation related SCI and delayed paralysis. The results showed that LAMP2A was upregulated in the SCI procedure, and contributed to neuron death and pro-inflammation perturbation via inducing iNOS⁺ polarization in microgila. We additionally observed that knockdown of LAMP2A resulted in the shift of microglia from iNOS⁺ to ARG1⁺ phenotype, as well as alleviated neuron damage during SCI. Furthermore, the analysis of BBB score, the result of immunohistological staining, and protein detection confirmed the activation of LAMP2A-mediated CMA activation and its interaction with NF-κB signaling, which leads to neuron death and motor function loss. These results prove that LAMP2A-mediated CMA contributes to the upregulation of pro-inflammatory cytokines and results in cell death in neurons during ischemic delayed paralysis via activating NF-κB signaling. Inhibition of LAMP2A promotes neurons survival during ischemic delayed paralysis.

Keywords: chaperone mediated autophagy; ischemic delayed paralysis; lysosome-associated membrane protein type 2A; microglia; spinal cord injury.